Silver based mercury film electrode part III. Comparison of theoretical and experimental anodic stripping results obtained for lead and copper

Abstract

The anodic stripping results obtained for lead and copper at an improved model of silver based mercury film electrode (SBMFE) were compared with theoretical predictions given for such a case by de Vries and van Dalen. During the study particular attention was paid to the formation of heterogenous amalgams and to influences which this effect could exert on the shape of the stripping peaks. Under conditions where homogenous amalgams were formed a good agreement was observed between theoretical and experimental results for peak currents ( i p ), shifts of the peak potential ( E p - E 1/2 ) and for half peak-widths ( b 1/2 ) obtained for the stripping of lead. On the other hand, small broadening of the values of b 1/2 and small decreasing of the values of i p were observed for copper compared to theoretical results. For heterogenous amalgams of both metals investigated the anodic displacement of the peak position was observed compared to the position predicted by the theory. The b 1/2 values observed under these conditions could increase, decrease or even stay unchanged depending on the scan rate used. The conditions where the significant increase of concentration of metal deposited into mercury film may lead to enhanced stripping signal were also discussed.